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The innate immune response to viruses is formed in part by interferon (IFN)-induced restriction factors, including ISG15, p21, and SAMHD1. IFN production can be blocked by the ISG15-specific protease USP18. HIV-1 has evolved to circumvent host immune surveillance. This mechanism might involve USP18. In our recent studies, we demonstrate that HIV-1 infection induces USP18, which dramatically enhances HIV-1 replication by abrogating the antiviral function of p21. USP18 downregulates p21 by accumulating misfolded dominant negative p53, which inactivates wild-type p53 transactivation, leading to the upregulation of key enzymes involved in de novo dNTP biosynthesis pathways and inactivated SAMHD1. Despite the USP18-mediated increase in HIV-1 DNA in infected cells, it is intriguing to note that the cGAS-STING-mediated sensing of the viral DNA is abrogated. Indeed, the expression of USP18 or knockout of ISG15 inhibits the sensing of HIV-1. We demonstrate that STING is ISGylated at residues K224, K236, K289, K347, K338, and K370. The inhibition of STING K289-linked ISGylation suppresses its oligomerization and IFN induction. We propose that human USP18 is a novel factor that potentially contributes in multiple ways to HIV-1 replication.
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http://dx.doi.org/10.3390/v16040485 | DOI Listing |
J Am Chem Soc
September 2025
Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Among the different types of HIV-1 maturation inhibitors, those that stabilize the junction between the capsid protein C-terminal domain (CA) and the spacer peptide 1 (SP1) within the immature Gag lattice are promising candidates for antiretroviral therapies. Here, we report the atomic-resolution structure of CA-SP1 assemblies with the small-molecule maturation inhibitor PF-46396 and the assembly cofactor inositol hexakisphosphate (IP6), determined by magic angle spinning (MAS) NMR spectroscopy. Our results reveal that although the two PF-46396 enantiomers exhibit distinct binding modes, they both possess similar anti-HIV potency.
View Article and Find Full Text PDFSci Signal
September 2025
Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, USA.
Replication of HIV-1 requires the coordinated action of host and viral transcription factors, most critically the viral transactivator Tat and the host nuclear factor κB (NF-κB). This activity is disrupted in infected cells that are cultured with extracellular vesicles (EVs) present in human semen, suggesting that they contain factors that could inform the development of new therapeutics. Here, we explored the contents of semen-derived EVs (SEVs) from uninfected donors and individuals with HIV-1 and identified host proteins that interacted with HIV Tat and the NF-κB subunit p65.
View Article and Find Full Text PDFPLoS Pathog
September 2025
INSERM UMR 1291, CNRS UMR 5051, Université de Toulouse, Toulouse Institute for Infectious and Inflammatory Diseases, Toulouse, France.
Vδ1 γδ T cells are key players in innate and adaptive immunity, particularly at mucosal interfaces such as the gut. An increase in circulating Vδ1 cells has long been observed in people with HIV-1, but remains poorly understood. We performed a comprehensive characterization of Vδ1 T cells in blood and duodenal intra-epithelial lymphocytes, obtained from endoscopic mucosal biopsies of 15 people with HIV-1 on antiretroviral therapy and 15 HIV-seronegative controls, in a substudy of the ANRS EP61 GALT study (NCT02906137).
View Article and Find Full Text PDFPLoS Biol
September 2025
Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, United States of America.
Despite the success of antiretroviral therapy in suppressing plasma viremia in people living with human immunodeficiency virus type-1 (HIV-1), persistent viral RNA expression in tissue reservoirs is observed and can contribute to HIV-1-induced immunopathology and comorbidities. Infection of long-lived innate immune cells, such as tissue-resident macrophages and microglia may contribute to persistent viral RNA production and chronic inflammation. We recently reported that de novo cytoplasmic expression of HIV-1 intron-containing RNA (icRNA) in macrophages and microglia leads to MDA5 and MAVS-dependent innate immune sensing and induction of type I IFN responses, demonstrating that HIV icRNA is a pathogen-associated molecular pattern (PAMP).
View Article and Find Full Text PDFFront Microbiol
August 2025
Institute of Infectious Diseases, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, Guangdong, China.
Introduction: Low-level viremia (LLV) in HIV infection, defined as detectable but low plasma viral load, is associated with an increased risk of virological failure (VF); however, the mechanisms underlying LLV remain unclear. Monocytes, as potential viral reservoirs, can migrate into tissues and differentiate into tissue-resident macrophage reservoirs, playing a critical role in viral dissemination and potentially driving persistent viremia.
Methods: This study aimed to analyze and compare the molecular characteristics of near-full-length HIV-1 proviral DNA quasispecies from monocytes in three distinct virological response groups: VF, LLV, and virological suppression (VS).